Method for making a draw string bag



July 27, 1965 I B. SAMWAYS 3,196,757

METHOD FOR MAKING A DRAW STRING BAG Filed July 29, 1963 s Sheets-Sheet 1 July 27, 1965 B. SAMWAYS 3,1 ,7 7

METHOD FOR MAKING A DRAW STRING BAG Filed July 29, 1963 3 Sheets-Sheet 2 July 27, 1965 B. SAMWAYS METHOD FOR MAKING A DRAW STRING BAG- 3 Sheets-Sheet 3 Filed July 29, 1963 United States Patent 3,196,757 METHOD FOR MAKING A DRAW TRING BAG Bruce Samways, Bristol, England, assignor to Colodense Limited, Bristol, England, a company of Great Britain and Northern Ireland Filed July 29, 1%3, Ser. No. 2%,172 Claims priority, application Great Britain, July 31, 1962, 29,392/ 62 9 Claims. (CI. 9335) This invention relates to draw-string bags.

Draw-string bags are well-known. They normally comprise a bag of a flexible material having open-ended tubular channels formed on each Wall adjacent the mouth of the bag through which strings, cords, or tapes are threaded and joined at their ends protruding from the channels to form loops. On pulling the loops of the strings, cords or tapes, the tubular channels are caused to gather up or shirr so closing the mouth of the bag.

Hitherto, in the manufacture of draw-string bags, the introduction of the draw-string into the tubular channels has entailed a slow, costly and difficult operation. Further, on storing or stacking the bags of the prior art, the free lengths of the draw-strings become entangled so that separation of the bags for filling purposes becomes a tiresome operation.

The present invention is concerned with a method of manufacturing an improved draw-string bag in which the disadvantages hitherto encountered are substantially reduced or eliminated.

Accordingly, the present invention includes a drawstring bag comprising a bag of a flexible material having a front-Wall and a rear wall in which a tubular channel is formed in each wall adjacent the mouth of the bag and a draw string is enclosed in each tubular channel, each draw-string being secured by one end within the channel at or adjacent to a selected edge of the bag and the second end of each draw string being detached or detachable from the corresponding tubular channel and capable of being gripped by finger pressure whereby the mouth of the bag may be substantially closed by shirring the tubular channels along the draw-strings towards the selected edge of the bag.

The draw-strings may be longer than the width of the bag when the second end of each draw-string protrudes from the end of each of the tubular channels so that the draw-strings may be gripped between the fingers for the operation of closing the bag.

Preferably, however, the length of each draw-string is substantially equal to the width of the bag when, in one form of the invention, a cut-away portion is provided in the ends of the tubular channels remote from the se lected edge of the bag to expose the second ends of each of the draw-strings.

In a preferred form of the invention, however, the draw-strings are secured at both or adjacent to both edges of the bag and, a portion of the bag defined by a line of weakness and including the two ends of the tubular channels to which the second ends of the draw-strings are secured, is detachable from the body of the bag to form a pulling tag for the draw-strings. The detachable portion of the bag may, for example, be the corner of the bag which includes the ends of the tubular channels to which the second ends of the draw-strings are secured and which is rendered detachable by finger pressure by a line of weakness such as a line of perforations or slits. More preferably, the detachable portion of the bag is confined to the ends of the tubular channels to which the second ends of the draw-strings are secured and may, for example, comprise semi-circular shaped portions, defined by a line of perforations or slits which may readily 'ice be nipped between the fingers and detached from the a body of the bag to form a pulling tag for the draw-strings.

As, in the preferred forms of the invention, the draw strings are substantially the same width as the bag, the draw-string bags may readily be manufactured in a continuous manner by forming an advancing web into a series of connected bags incorporating continuous drawstrings followed by separating the individual completed bags from the web.

Accordingly, the present invention also includes a continuous method for the manufacture of draw-string bags comprising forming hems with draw-string access portions at predetermined bag width intervals at bag mouth forming margins of an advancing web of flexible material, enclosing continuous draw-strings within the hems, sealing the edge of each hem to the body of the Web to form a tubular channel enclosing a draw-string, sealing the web with the tubular channels lying in juxtaposition along strips adjacent each draw-string access portion to define a series of connected bags and to seal the portions of draw-strings passing through the strips of the tubular channels and during or after the transverse sealing operation, separating the individual bags along lines passing substantial-1y centrally through the strips.

The advancing web may be a flat sheet which, prior to the transverse sealing operation is folded along its longitudinal axis so that the tubular channel formed at the bag mouth forming edges of the sheet lie in juxtaposition.

The advancing web may also be a length of tubular material in a lay flat state which is slit longitudinally down one edge to form bag-mouth forming margins.

The advancing web may also be a length of tubular material having a longitudinal pleat which defines bag mouth forming margins and which is slit down the centre of the pleat to form a folded sheet having hems at the edges.

The flexible material is conveniently a heatsealable material, for example, a film such as polyethylene, .when all the sealing operations may be heat-sealing operations. The transverse strips along which the web is sealed to form a series of connected bags may comprise a solid heat-sealed area and the bags may be separated by cutting substantially centrally through the strips by means of a hot knife, a hot wire or by pulling the bags apart while the seal is still in a hot plastic condition. Alternatively, the transverse strips may comprise at least two closely spaced parallel heat-seal lines when the bags may be separated by cutting through the unsealed portion between the lines.

The flexible material may be secured by means other than heat-sealing, for example by stitching when the transverse strips are defined by at least two adjacent parallel rows of stitching.

The draw-string access portions may be formed in the web before or after the formation of the hems but before the insertion of the draw-strings in the hems.

The draw-string access portions may be cut-away portions which in the completed bag expose the ends of the web at one edge of the bag. During the transverse sealing operation, the draw-strings exposed at the cut-away portion may be sealed together such that when the individual bags are separated, the joined ends of the exposed draw-strings form a convenient finger tab for pulling the strings- The cut-away portion may be formed by the action of a reciprocating knife.

More preferably, however, the draw-string access portion is a selected portion of the web defined by a line of weakening, for example a line of perforations or slits, to form, in the completed bag, a detachable pulling tag to which the ends of the draw-strings are secured. The de- Patented July 27, 1965 tachable pulling tag may be a corner of the bag or more preferably, a semicircular shaped portion defined by a line of weakening confined to the ends of the tubular channels to which the draw-strings are secured. The detachable pulling tags may be formed by a reciprocating perforating or other web weakening means.

The draw-strings may be ribbons of any suitable material, but where the sealing operations are heat-seal operations, the draw-strings are preferably formed from a heat-scalable material. The draw-strings may conveniently be formed by cutting thin ribbons of the web material from the bag mouth forming margins or the free edges of the hems when they are then guided into the hems just prior to the edges of the hems being sealed to the body of the bag to form tubular channels.

In the form of the invention where a pleated tube is slit to form a folded web with a hem. at each edge, the pleat may be W in shape when on slitting down the centre of the pleat and also along the valleys or the side walls of the pleat, hems are formed in the folded web and ribbons are made available for use as draw-strings.

Specific methods of manufacturing draw-string bags in accordance with the invention will now be described with reference to the accompanying drawings in which:

FIGURE 1 is a diagrammatic illustration of the first series of one set of processing steps,

FIGURE 2 is a diagrammatic illustration of the concluding series of the processing. steps following FIG- URE 1,

FIGURE 3 is an enlarged front elevation of one form of a finished bag,

FIGURE 4 is a section through 4-4 of FIGURE 3,

FIGURE 5 is a bag as shown in FIGURE 3 at the commencement of the closing operation,

FIGURE'6 is a bag as shown in FIGURE 5 at the completion of the closing operation,

FIGURE 7 is an enlarged front elevation of a second form of finished bag,

FIGURES 8-12 are diagrammatic cross-sections through a tubular web showing a second set of processing steps for manufacturing draw-string bags.

Referring to FIGURE 1, a web 1 of polyethylene film, eighteen inches wide and 0.001 inch thick, is advanced in the direction shown by the arrow. At each edge of the web, lines of slits 2 are formed at intervals corresponding with the desired width of the bags to be manufactured. Each line of slits 2 extends transversely across the web 1 for a distance of 2% inches and then curves in the direction of travel of the web for a distance of /2 inch thus partly defining a draw-string access portion of the web which will eventually become a pulling tab as hereinafter described.

Draw-strings 3 are fed along the margin of the web 1 at the same speed as the travel of the web 1. The drawstrings 3 consist of polyethylene ribbons, inch wide and 0.002 inch thick. The edges of the web 1 are then folded over the draw-strings 3 to form hems 4, inch deep, and the edges of the hems 4 are heat-sealed along longitudinal strips 5 to form tubular channels 6 enclosing the draw-strings 3. Referring to FIGURE 2, the web 1 is then folded along its longitudinal axis so that the tubular channels 6 lie in juxtaposition and the folded web 1 is heat-sealed transversely along transverse strips 7 at positions where the curved ends of the lines of slits 2 just enter the transverse strips 7, to define bag portions h. During the formation of the transverse strips 7, the inner walls of the tubular channels 6 are sealed together and to the portions of the draw-strings 3 within the area of the strips 7. The individual bags 9 are then severed from the web 1 by cutting centrally through the transverse heat-seal strips 7.

Referring to FIGURES 3 and 4, each bag 9 has a mouth 10 bordered by tubular channels 6 in which draw-strings 3 are enclosed and sealed at both ends within the side walls 11 of the bag 9. One corner of the bag forms a detachable pulling tag 12 defined by the lines of slits 2 til and includes the sealed ends of the two tubular channels 6 and the ends of the two draw-strings 3 which, as previously stated, are sealed within the side wall 11 of the pulling tag 12. v

The closure of the bag 9 (FIGURES 5 and 6) is effected by detaching the pulling tag 12 from the body of the bag 9 by tearing along the lines of slits 2, and pulling the tag 12. against the bag 9, when the tubular channels are caused to shirr and constrict the mouth 10 of the bag 9.

Referring to FIGURE 7, a bag 9' has the same features as the bag 9 illustrated in FIGURES 3, 4, 5 and 6 with the exception that the detachable pulling tag consists of a semicircular portion 12 defined by a line of perforations which is confined to the ends of the tubular channels 6 to which the draw-strings 3 are secured.

FIGURES 8 to 12 illustrate a second method of manufacturing draw-string bags in accordance with the invention from an advancing tubular film 13 of polyethylene.

The tubular film 13 (FIGURE 8) is pleated with a W-shaped pleat 14 (FIGURE 9) by means not shown, but which may consist of a nip formed between a grooved wheel and a disc pressed into the groove.

Suitable draw-string access portions (not shown) are then cut out or defined by a line of perforations'at bag width intervals in the folded edges 15 of the pleat 14 by reciprocating cutter 16 (FIGURE 10).

The film 13 is then slit centrally down the centre of the pleat 14 and along each of the side walls of the pleat 14 (FIGURE 11) to form hems 17 and V-shaped drawstrings 18. The draw-strings 18 are then led into the hems 17 (FIGURE 12).

After sealing the edges of the hems 17 to form tubular channels (not shown), the slit film 13 is heat-sealed transversely at intervals corresponding with the drawstring access portions and individual bags are separated by the procedure described with reference to FIGURE 2.

The method in accordance with the invention provides a convenient continuous method of manufacture of drawstring bags of improved construction in which a separate discontinuous step of inserting draw-strings is avoided.

What I claim and desire to secure by Letters Patent is:

1. A continuous method for the manufacture of draw string bags comprising advancing a continuous web of a heat scalable flexible sheet material, forming a hem at each bag mouth forming margin of the web with selected portions defined by lines of weakness formed in the hems at bag width intervals to form detachable puiling tags in the completed bags, inserting draw strings in the hems at the same speed as the speed of travel of the web, sealing the open edges of the hems to the body of the web to form tubular channels enclosing the-draw strings and, with the hems at the bag mouth forming margins lying in juxtaposition, sealing and severing the web transversely at bag width intervals coincident with an edge of each selected portion so as to seal portions of the draw strings intersected by the seals within'the tubular channels and to separate individual bags with sealed side margins from the web.

2. A continuous method as claimed in claim 1 in which each selected portion is a semicircular portion defined by forming a C-shapedline of perforations substantially centrally in the body of the hem and the Web is sealed and severed transversely along a line passing through the straight edge of the semicircular portion.

3. A continuous method as claimed in claim 1 in which the continuous web is a flat sheet in Which each longitudinal edge is a bag mouth forming margin.

4. A continuous method as claimed in claim 1 in which the continuous web is a tube and includesthe step of slitting the tube longitudinally to form bag mouth forming margins.

5. A continuous method for the manufacture of draw string bags comprising advancing a continuous web of a heat scalable flexible sheet material, forming a hem at each bag mouth forming margin of the Web with selected portions defined by lines of weakness formed in the hems at bag width intervals to form detachable pulling tags in the completed bags, continuously trimming at least two strips from the web to form draw strings, inserting the draw strings in the hems at the same speed as the speed of travel of the Web, sealing the open edges of the hems to the body of the web to form tubular channels enclosing the draw strings and, with the hems at the bag mouth forming margins lying in juxtaposition, sealing and severing the Web transversely at bag width intervals coincident with an edge of each selected portion so as to seal portions of the draw strings intersected by the seals within the tubular channels and to separate individual bags with sealed side margins from the web.

6. A continuous method for the manufacture of draw string bags comprising advancing a continuous tube of a heat scalable flexible sheet material, forming a longitudinal W-shaped pleat in the tubular film, forming draw string access portions in the hem forming edges of the pleat at bag width intervals, continuously slitting the tube down the center of the pleat and along lines spaced either side of the center of the pleat to form two hems and at least two strips forming draw strings, inserting the draw strings in the hems at the same speed as the speed of travel of the slit tube, sealing the open edges of the hems to the body of slit tube to form tubular channels enclosing the draw strings and with the hems at the bag mouth forming margins in juxtaposition, sealing and severing the slit tube transversely at bag width intervals coincident with an edge of a draw string access portion so as to seal portions of the draw strings intersected by the seals within the tubular channels and to separate individual bags with sealed side margins from the slit tube.

7. A continuous method for the manufacture of draw string bags comprising advancing a continuous web of a heat scalable flexible sheet material, forming a hem at each bag mouth forming margin of the web, continously trimming at least two strips from the web to form draw strings, inserting the draw strings in the hems at the same speed as the speed of travel of the web, sealing the open edges of the hems to the body of the web to form tubular channels enclosing draw strings and with the hems at the bag mouth forming margins lying in juxtaposition, sealing and severing the web transversely atbag Width intervals to separate individual bags with sealed side margins from the web.

8. The method of manufacturing a plurality of draw string bags which comprises advancing a continuous sheet of flexible heat sealable material, the width of said sheet material being twice that of the depth of the desired draw string bag, scoring each edge of said sheet to form tab portions on each at distances equal to the desired width of said draw string bag, each of said tab portions being outlined by weakened material along said scoring, feeding draw strings of heat sealable, flexible material along each longitudinal edge of said sheet and at the same rate as the movement of said sheet, folding over each longitudinal edge to enclose its respective draw string, heat sealing each folded-over edge to said sheet to form tubular channels enclosing said draw strings,

folding said sheet to bring said tubular channels on each edge into contact, heat sealing said folded sheet along lines transverse to the longitudinal axis thereof and separated by intervals corresponding to the desired width of each of said draw string bags, said heat sealing along transverse lines simultaneously fusing said folded sheets together to form the sides of said bags, fusing said tubular channels to one end of the draw string enclosed and fusing said tab portions at the other end thereof, and cutting said draw string'bags apart along said transverse fused lines to form each bag, said tab portion being separable from said bag along said scoring by pulling thereof to enable closing of said bag as said tab portion and attached 'draw string is pulled.

9. The method of manufacturing a plurality of draw string bags from a continuous tube of heat sealable, flexible material which comprises forming a longitudinally extending W-shaped pleat in said tube, the terminal margins of said pleat and the sides of the tube of material constituting a hem on each side of said pleat, said hems defining the mouth portion of the draw string bags, scoring each hem to form tab portions at distances equal to the desired width of said draw string bag, each of said tab portions being outlined by weakened material along said scoring, cutting said pleat longitudinally at the midpoint of said pleat, severing strips from the edge of said longitudinal cut to serve as draw strings, positioning each of said severed strips within a respective hem, heat sealing the edge of said pleat to said tubular material to form tubular channels enclosing each of said draw strings, heat sealing said tubular channel along lines transverse to the longitudinal axis thereof and separated by intervals corresponding to the desired width of each of said draw string bags, said heat sealing along transverse lines simultaneously fusing the sides of said tube together to form the sides of said desired bags, fusing said tubular channels to one end of the draw strings enclosed therein and fusing said tab portions to the other end of the draw string, and cut ting said draw string bags apart along said transverse fused lines to form each bag, said tab portion being separable from said formed bag along said scoring by pulling thereof to enable closing of said bag as said tab portion and attached draw string is pulled.

References Cited by the Examiner UNITED STATES PATENTS 1,861,864 6/32 Kennedy.

2,777,491 1/57 Ashton et a1.

2,798,523 7/62 Barrett.

3,046,847 7/ 62 Voege et a1 9335 3,058,403 10/ 62 Kugler.

3,060,815 10/ 62 Honsel 9335 3,061,169 10/ 62 Yermakofi' et a1.

3,079,844 3/63 Kugler 93-35 3,093,295 6/63 Kugler 22963 3,094,269 6/ 63 Schneider.

3,119,549 1/ 64 Schoen 22962 X FRANK E. BAILEY, Primary Examiner.

FRANKLIN T. GARRETT, BERNARD STICKNEY, Examiners. 

1. A CONTINUOUS METHOD FOR THE MANUFACTURE OF DRAW STRING BAGS COMPRISING ADVANCING A CONTINOUS WEB OF A HEAT SEALABLE FLEXIBLE SHEET MATERIAL, FORMING A HEM AT EACH BAG MOUTH FORMING MARGIN OF THE WEB WITH SELECTED PORTIONS DEFINED BY LINES OF WEAKNESS FORMED IN THE HEMS AT BAG WIDTH INTERVALS TO FORM DETACHABLE PULLING TAGS IN THE COMPLETED BAGS, INSERTING DRAW STRINGS IN THE HEMS AT THE SAME SPEED AS THE SPEED OF TRAVEL OF THE WEB, SEALING THE OPEN EDGES OF THE HEMS TO THE BODY OF THE WEB TO FORM TUBULAR CHANNELS ENCLOSING THE DRAW STRINGS AND, WITH THE HEMS AT THE BAG MOUTH FORMING MARGINS LYING IN JUXTAPOSITION, SEALING AND SEVERING THE WEB TRANSVERSELY AT BAG WIDTH INTERVALS COINCIDENT WITH AN EDGE OF EACH SELECTED PORTION SO ASS TO SEAL PORTIONS OF THE DRAW STRINGS INTERSECTED BY THE SEALS WITHIN THE TUBULAR CHANNELS AND TO SEPARATE INDIVIDUAL BAGS WITH SEALED SIDE MARGINS FROM THE WEB. 